The present invention relates to a lock apparatus and in particular to a lock apparatus mountable to a pipe communicating with a storage tank to prevent unauthorized withdrawals from the storage tank and undesired leakage of contaminants into the storage tank.
With the advent of increasing gasoline prices, a serious problem of theft has arisen whereby individuals insert a hose into a storage tank at a gasoline station through the fuel input pipe communicating with an underground storage tank. The fuel is then pumped from the underground storage tank thereby effecting a theft of the fuel.
Various devices have been devised to prevent such unauthorized withdrawals. However, these devices have generally been in the form of a lock-on cap mechanism which is inserted over the top of the communicating pipe. For example, one such cap mechanism incorporates a lock flange which extends upwardly from the top surface of the cap and a latch which is pivotally mounted to the side of the cap. The latch is then pivotal between a locked and an unlocked position with the lock flange being positioned in such a way that when the latch is pivoted to the locked position a padlock can be inserted into a hole in the lock flange to prevent pivotal movement of the latch to the unlocked position.
Although this and other similar cap type lock devices prevent access to the underground storage tank through the pipe, it has been found that such caps can be easily removed by exerting pressure with a crowbar or the like against either the latch or the lock flange to break either the latch or the lock flange. Consequently, there is a need for a more secure locking mechanism to prevent thefts of gasoline or other flowable substance from storage tanks.
The present invention provides such an improved lock mechanism by providing an open ended cylindrical housing for attachment to the top of the input pipe. The cylindrical housing includes a radially mounted valve mechanism which is pivotal in the interior of the housing between an opened and a closed position. The valve mechanism includes a shaft or axle which has one end extending through an orifice in the side of the cylindrical housing. A latch is then pivotally attached to the protruding end of the axle with a lock flange being affixed to the outside surface of the housing whereby the latch and the lock flange are aligned for interconnecting to one another when the valve is in the closed position. A suitable padlock or other locking device can then be attached to the lock flange to maintain the coupled relationship of the lock flange and the latch. A suitable tamper prevention flange is provided to extend outwardly from the housing immediately above the protruding end of the axle. The tamper prevention flange is positioned to protect the axle and the latch and prevent the insertion of a prying device to effect a breaking of the latch or axle.
The valve mechanism includes a sandwiched plate assembly including a first rigid plate member having a circumferential edge positioned in spaced relationship with the housing, a second rigid plate member having a circumferential edge likewise positioned in spaced relationship with the housing and a generally disc like resilient member sandwiched between the first and second rigid plates and extending beyond the circumferential edges of the first and second rigid plates for contacting and sealing the space between the inside surface of the housing and the circumferential edges of the first and second rigid plates.
The portion of the resilient member protruding beyond the edge of the rigid plates comprise a seal which additionally prevents a foreign substance such as water from passing through the pipe and into the storage tank. Thus, the valve mechanism serves the purpose of not only preventing a foreign object from being inserted into the storage tank through the pipe for the purpose of making an unauthorized withdrawal from the storage tank but also preventing foreign substances from being introduced into the storage tank through the pipe.